Tìm số tự nhiên x biết
a) (19x + 2.52):14 = (13 – 8)2 – 42
b) 2.3x = 10.312 + 8.274
help meeeeeeeeeeee
Tìm số tự nhiên x biết
a) (19x + 2.52):14 = (13 – 8)2 – 42
b) 2.3x = 10.312 + 8.27
ai rảnh giúp mk với nhé
a) \(\left(19x-2.52\right):14=\left(13-8\right).2-42\)
\(\left(19x-50\right):14=10-42\)
\(\left(19x-50\right):14=-32\)
\(19x-50=-448\)
\(19x=-398\)
\(x=-\dfrac{398}{19}\)
( 19x + 2.52 ) : 14= (13 - 8)2 - 4 tìm x
\(...\Rightarrow\left(19x+50\right):14=5^2-4\Rightarrow\left(19x+50\right):14=21\Rightarrow\left(19x+50\right)=21.14\)
\(\Rightarrow19x+50=294\Rightarrow19x=244\Rightarrow x=\dfrac{244}{19}\)
Tìm x
(19x+2.52) :14= (13-8)2 - 42
\(\left(19x+2.5^2\right):14=\left(13-8\right)^2-4^2\)
\(\Rightarrow\left(19x+50\right):14=5^2-4^2\)
\(\Rightarrow\left(19x+50\right):14=9\)
\(\Rightarrow19x+50=126\)
\(\Rightarrow19x=76\)
\(\Rightarrow x=4\)
Vậy x = 4
#Kễnh
a) 3+2x-1 = 24 - [ 42-(22-1) ]
b) (19x+2.52):14 = (13-8)2-42
a) 3+2x-1 = 24 - [ 42-(22-1) ]
b) (19x+2.52):14 = (13-8)2 - 42
\(a,\Rightarrow2^{x-1}=24-\left(16-3\right)-3\\ \Rightarrow2^{x-1}=24-13-3\\ \Rightarrow2^{x-1}=8=2^3\\ \Rightarrow x-1=3\Rightarrow x=4\\ b,\Rightarrow\left(19x+50\right):14=25-16=9\\ \Rightarrow19x+50=126\\ \Rightarrow x=4\)
Bài 5.Tìm x N, sao cho:
a)3636 : (12x –91) = 36
b)(x : 23 + 45) . 67 = 8911
c)[(6x –39) : 7]. 4 = 12
d)(3x –24). 73= 2. 74
e)x(x –10) = 0
f)(x+ 1). (x –2) = 0
g)(9 –x)3= 64
h)3x= 81
i)2 . 3x= 10 . 312+ 8 . 312
j)(19x + 2.52) : 14 = (13 -8)2-42
\(a,\Rightarrow12x-91=101\\ \Rightarrow12x=192\\ \Rightarrow x=16\\ b,\Rightarrow x:23+45=133\\ \Rightarrow x:23=88\\ \Rightarrow x=\dfrac{88}{23}\\ c,\Rightarrow\left(6x-39\right):7=3\\ \Rightarrow6x-39=21\\ \Rightarrow6x=60\\ \Rightarrow x=10\\ d,\Rightarrow3x-24=\dfrac{148}{73}\\ \Rightarrow3x=\dfrac{1900}{73}\\ \Rightarrow x=\dfrac{1900}{219}\\ e,\Rightarrow\left[{}\begin{matrix}x=0\\x=10\end{matrix}\right.\\ f,\Rightarrow\left[{}\begin{matrix}x=-1\\x=2\end{matrix}\right.\\ d,\left(9-x\right)^3=64=4^3\\ \Rightarrow9-x=4\\ \Rightarrow x=5\\ h,\Rightarrow x=27\\ i,\Rightarrow6x=312\cdot12=624\cdot6\\ \Rightarrow x=624\\ j,\Rightarrow\left(19x+104\right):14=25-42=-17\\ \Rightarrow19x+104=-238\\ \Rightarrow19x=-342\\ \Rightarrow x=-18\)
Tìm số tự nhiên x biết :
a, 2.(x – 5)+7 = 77
b, x - 1 3 - 3 5 : 3 4 + 2 . 2 3 = 14
c, 1 + 2 + 2 2 + 2 3 + . . . + 2 2016 = 2 x - 1 - 1
d, 5 2 x - 3 - 2 . 5 2 = 5 2 . 3
a, 2.(x – 5)+7 = 77
<=> 2.(x – 5) = 70 <=> x – 5 = 35 <=> x = 40
b, x - 1 3 - 3 5 : 3 4 + 2 . 2 3 = 14
<=> x - 1 3 - 3 + 2 4 = 14
<=> x - 1 3 = 14 + 3 - 16 = 1
<=> x – 1 = 1 <=> x = 2
c, 1 + 2 + 2 2 + 2 3 + . . . + 2 2016 = 2 x - 1 - 1
Đặt: A = 1 + 2 + 2 2 + 2 3 + . . . + 2 2016 => 2A = 2 + 2 2 + 2 3 + . . . + 2 2017
=> 2A – A = ( 2 + 2 2 + 2 3 + . . . + 2 2017 ) – ( 1 + 2 + 2 2 + 2 3 + . . . + 2 2016 )
=> A = 2 2017 - 1
Ta có: 1 + 2 + 2 2 + 2 3 + . . . + 2 2016 = 2 x - 1 - 1 => 2 2017 - 1 = 2 x - 1 - 1 => x = 2018
d, 5 2 x - 3 - 2 . 5 2 = 5 2 . 3
<=> 5 2 x - 3 = 5 2 . 3 + 5 2 . 2
<=> 5 2 x - 3 = 5 2 . ( 3 + 2 )
<=> 5 2 x - 3 = 5 3
<=> 2x – 3 = 3 => x = 3
2.3x =10.312 +8.274
tìm x
\(\Rightarrow6x=5312\)
\(\Rightarrow x=5312:6\)
\(\Rightarrow x=885,3333333\)
tíc nha
\(2.3x=10.312+8.274\)
\(=2.3x=3120+2192\)
\(2.3x=5312\)
\(3x=5312:2\)
\(3x=2656\)
\(x=2656:3\)
\(x=\frac{2556}{3}\)
BT1 : Tìm x biết :
a, (7x - 11)3 = 25.52 + 200
b, 720 : (41 - ( 2x - 5 )) = 23.5
c, 2.3x = 10.312 + 8.274
Bài 1: Tìm x
a) Ta có: \(\left(7x-11\right)^3=2^5\cdot5^2+200\)
\(\Leftrightarrow\left(7x-11\right)^3=32\cdot25+200=1000\)
\(\Leftrightarrow7x-11=10\)
\(\Leftrightarrow7x=21\)
hay x=3
Vậy: x=3
b) Ta có: \(720:\left(41-\left(2x-5\right)\right)=2^3\cdot5\)
\(\Leftrightarrow720:\left(41-2x+5\right)=8\cdot5=40\)
\(\Leftrightarrow-2x+46=18\)
\(\Leftrightarrow-2x=18-46=-28\)
hay x=14
Vậy: x=14
c) Ta có: \(2\cdot3^x=10\cdot3^{12}+8\cdot27^4\)
\(\Leftrightarrow2\cdot3^x=10\cdot3^{12}+8\cdot3^{12}\)
\(\Leftrightarrow2\cdot3^x=18\cdot3^{12}\)
\(\Leftrightarrow3^x=\dfrac{18\cdot3^{12}}{2}=9\cdot3^{12}\)
\(\Leftrightarrow3^x=3^2\cdot3^{12}=3^{14}\)
hay x=14
Vậy: x=14
A (7x-11)3=25.52+200
(7x-11)3=800+200
(7x-11)3=1000
(7x-11)3=103
7x-11=10
7x=10+11
7x=21
x=21:7
x=3
B 720:(41-(2x-5))=23.5
720:(41-(2x-5))=40
41-(2x-5)=720:40
41-(2x-5)=18
2x-5=41-18
2x-5=23
2x=23+5
2x=28
x=28:2
x=14
C 2.3x=10.312+8.274
2.3x=10.312+8.(33.4)
2.3x=10.312+8.312
2.3x=312.(10+8)
2.3x=312.18
3x=( 312.18):2
3x=312.9
3x=312 .32
3x=314
3x=14
x=14